WO2020115204A1

WO2020115204A1 - Method for replacing a mirror in a projection exposure apparatus, and position- and orientation data measuring device for carrying out the method

Info

Publication number: WO2020115204A1
Application number: PCT/EP2019/083811
Authority: WO
Inventors: Christoph Petri; Daniel Runde; Florian Baumer; Ulrich Müller
Original assignee: Carl Zeiss Smt Gmbh
Priority date: 2018-12-06
Filing date: 2019-12-05
Publication date: 2020-06-11
Also published as: DE102018221128A1; TW202032282A; KR20210099078A; US11500294B2; US20210294222A1; TWI835940B

Abstract

When replacing a mirror in a projection exposure apparatus, a mirror for replacement is initially removed (41). Position- and orientation data of the removed mirror for replacement are measured (43) by a position- and orientation data measuring device. Furthermore, position- and orientation data of a replacement mirror, which should be inserted in place of the mirror for replacement, are measured (46) using the position- and orientation data measuring device. Bearing points of the replacement mirror are reworked (48) on the basis of ascertained differences between, firstly, the position- and orientation data of the mirror for replacement and, secondly, the position- and orientation data of the replacement mirror. The reworked replacement mirror is installed (54). This yields a mirror replacement method, in which an adjustment outlay of the replacement mirror in the projection exposure apparatus is reduced.

Description

Method for replacing a mirror in a projection exposure apparatus, and position- and orientation data measuring device for carrying out the method

The present application claims priority of German patent application DE 10 2018 221 128.0, the content of which is incorporated herein by reference.

The invention relates to a method for replacing a mirror in a projection exposure appa ratus. Further, the invention relates to a position- and orientation data measuring de vice for carrying out such a method.

The operation of a projection exposure apparatus for producing semiconductor compo nents with micrometre structures and nanometre structures requires optical units that ensure a correspondingly high resolution. This high resolution can only be ensured if the optical component parts are aligned with respect to one another with a high posi tional accuracy. Therefore, the replacement of a mirror within a projection exposure apparatus requires extremely high positioning accuracy and was previously linked to high adjustment outlay.

A position- and orientation data measuring device is known from DE 10 2012 209 412 Al. A system adjustment of illumination systems is described in DE 10 2016 203 990 Al.

It is an object of the present invention to develop a mirror replacement method of the type set forth at the outset in such a way that an adjustment outlay of the replacement mirror in the projection exposure apparatus is reduced.

According to the invention, this object is achieved by a replacement method including the features specified in Claim 1. Angle- and position data of an optical surface can be measured relative to mechanical references using the position- and orientation measuring device. The position- and ori entation data may contain all six rigid body degrees of freedom, i.e., the three degrees of freedom of translation and the three degrees of freedom of rotation. If an orientation and position of an optical surface of the mirror is known relative to the bearing points and if the positions, or positions and orientations, of the bearing points of a mirror for replacement are known, it is sufficient, in principle, to exactly reproduce the positions, or positions and orientations, of these bearing points on the replacement mirror. Pro vided this bearing point positioning is perfect and implemented without a residual er ror, a mirror surface of the replacement mirror, following the installation of the re placement mirror, is ensured to be positioned at exactly the same location as the mirror surface of the originally installed mirror for replacement, and no further adjustments are necessary. In other cases, an adjustment outlay can be significantly reduced in comparison with a replacement method without measuring and reworking bearing points of the replacement mirror.

Depending on the configuration of the replacement method, a measurement by the po sition- and orientation data measuring device of position- and orientation data of the mirror for replacement, said measurement following a removal of the mirror for re placement, can be implemented as constituent part of the replacement method. Alter natively, it is possible to use position- and orientation data of the removed mirror for replacement, said data having been measured in advance.

The position- and orientation data of the replacement mirror can also be measured prior to the position- and orientation data of the mirror for replacement. In order to measure the position- and orientation data, use can be made of a position- and orienta tion data measuring device as is already known, in principle, from DE 10 2012 209 412 Al. Measuring the position- and orientation data according to Claim 2 avoids problems with drift. Here, a sequence of the measurement is not necessarily important.

Absolute position- and orientation data measurement accuracy need not be achieved; instead, it is sufficient to obtain a high relative measurement accuracy between the measurement of the mirror for replacement and the measurement of the replacement mirror.

Measuring the position- and orientation data of, firstly, the mirror for replacement and, secondly, the replacement mirror, can be implemented within a day, can be imple mented within 12 hours and, in particular, can be implemented within a shorter period of time, for example within two hours or within one hour.

Measuring the position- and orientation data at the same location according to Claim 3 avoids position- and orientation data errors that may arise on account of an overall dis placement of the position- and orientation data measuring device.

Reworking the bearing points according to Claim 4 or 5 was found to be particularly suitable. As an alternative or in addition thereto, there can also be a plastic defor mation of the bearing points during the reworking.

When replacing a facet mirror according to Claim 6, the advantages of the replacement method come into effect particularly well. The facet mirror can be a pupil facet mirror or a field facet mirror of an illumination optical unit of the projection exposure appa ratus. Alternatively, the mirror for replacement may also be any other mirror of the il lumination optical unit, a collector disposed directly downstream of an illumination light source or else a mirror of the projection optical unit of the projection exposure apparatus for imaging a reticle-side object field into a wafer-side image field. Reproducing an illumination beam path according to Claim 7 leads to a particularly sensitive position- and orientation data measurement. When reproducing the illumina tion beam path, a beam direction and/or a beam diameter and/or a beam divergence of measurement light can be reproduced according to the corresponding parameters of the illumination light in such a way that these parameters correspond to one another within predetermined tolerances. The beam direction of a reproduced measurement light beam path can run counter to that of the illumination beam path.

Considering an illumination channel subset according to Claim 8 simplifies the posi tion- and orientation data measuring steps. When measuring the position- and orienta tion data, a global tilt of the individual channels, i.e., a mean value of a tilt of the indi vidual channels, can be measured.

Selecting the subset according to Claim 9 leads to the possibility of a position- and ori entation data measurement during the replacement method, which is adapted to the practical use of the mirror for replacement during the operation of the projection expo sure apparatus.

Stopping down according to Claim 10 facilitates a simple subset selection.

The advantages of a position- and orientation data measuring device according to Claim 11 correspond to those that have already been explained above with reference to the replacement method according to the invention.

For the position- and orientation data measuring device, use can be made, in principle, of that according to DE 10 2012 209 412 Al, following the adaptation to the necessity of measuring both the mirror for replacement and the replacement mirror. In principle, the advantages of a position- and orientation data measuring device ac cording to Claim 12 correspond to those which were already explained above in con junction with Claims 6 and 8. On account of the reduction of the considered illumina tion channels to a subset, there is a corresponding simplification of the measurement process to be carried out using the position- and orientation data measuring device.

The ascertainment of a multiplicity of position- and orientation data that, in principle, are redundant can be avoided.

The position- and orientation data measuring device has an imaging optical unit for imaging the stop onto an arrangement plane of the mirror holder. Such an imaging op tical unit facilitates the selection of very specific portions of a measurement light beam cross section that is possible overall.

Arrangements of the stop according to Claim 13 facilitate simple stopping-down of non-required components of a measurement light beam.

By way of a corresponding stop configuration, it is possible, in particular, to select a subset selection of illumination channels to be measured, which corresponds to an illu mination setting of a projection exposure apparatus in which the mirror to be measured is used. Then, the position- and orientation data measuring device is well adapted to the practical use of the mirror to be measured, during operation within the projection exposure apparatus.

The component to be produced by the projection exposure apparatus can be a micro chip and, for example, a memory chip.

Exemplary embodiments of the invention are explained in greater detail below with reference to the drawing. In said drawings:

Fig. 1 shows a microlithographic projection exposure apparatus schematically and with respect to an illumination optical unit in a meridional section; Fig. 2 shows a plan view on a facet arrangement of a field facet mirror of the illumination optical unit of the projection exposure apparatus according to Figure 1;

Fig. 3 shows a plan view on a facet arrangement of a pupil facet mirror of the illumination optical unit of the projection exposure apparatus according to Figure 1;

Fig. 4 shows, in an illustration similar to Figure 2, a facet arrangement of a fur ther embodiment of a field facet mirror;

Fig. 5 schematically shows a position- and orientation data measuring device for measuring the position- and orientation data of a facet mirror for re placement in a projection exposure apparatus;

Fig. 6 shows a measurement light beam path of an embodiment of the position- and orientation data measuring device between a light source and the facet mirror to be measured, wherein a first embodiment of a stop for stopping down facet illumination channels that should not be measured is disposed in the beam path;

Fig. 7 and 8 each show, in an illustration similar to Figure 5, further arrangement var iants of stops for stopping down facet illumination channels that should not be measured;

Fig. 9 shows a flowchart of a method for replacing a mirror in the projection exposure apparatus, containing a measurement of position- and orienta tion data of a mirror for replacement and of a replacement mirror, in each case with one of the variants of the position- and orientation data measur ing device;

Fig. 10 schematically shows a side view of the facet mirror for replacement;

Fig. 11 shows the replacement mirror in a view similar to Figure 10;

Fig. 12 shows, in a view similar to Figures 10 and 11, a measurement receptacle of the position- and orientation data measuring device for receiving the mirror for replacement or the replacement mirror;

Fig. 13 schematically shows, in a view similar to Figures 10 to 12, a beam path in the position- and orientation data measuring device when measuring the mirror for replacement according to Figure 10;

Fig. 14 shows, in an illustration similar to Figure 13, the beam path in the posi tion- and orientation data measuring device when measuring the replace ment mirror according to Figure 11;

Fig. 15 shows, in an illustration similar to Figures 10 and 11, the replacement mirror following reworking of the bearing points thereof on the basis of ascertained differences between the position- and orientation data of, firstly, the mirror for replacement and, secondly, the replacement mirror, which were measured with the aid of the position- and orientation data measuring device;

Fig. 16 shows, in an illustration similar to Figures 10 to 15, the mirror for re placement in a bearing receptacle of the projection exposure apparatus; and Fig. 17 shows, in an illustration similar to Figure 16, the replacement mirror fol lowing the reworking of the bearing points thereof in the bearing recepta cle according to Figure 16.

A microlithographic projection exposure apparatus 1 serves for producing a micro- structured or nanostructured electronic semiconductor component. A light source 2 emits EUV radiation used for illumination in the wavelength range of, for example, between 5 nm and 30 nm. The light source 2 can be a GDPP (gas discharge produced plasma) source or an LPP (laser produced plasma) source. A radiation source based on a synchrotron can also be used for the light source 2. Information about such a light source can be found by a person skilled in the art in US 6,859,515 B2, for example. EUV illumination light or illumination radiation 3 is used for illumination and imaging within the projection exposure apparatus 1. The EUV illumination light 3 downstream of the light source 2 firstly passes through a collector 4, which can be, for example, a nested collector having a multi-shell construction known from the prior art, or alterna tively an ellipsoidally shaped collector. A corresponding collector is known from EP 1 225 481 A2. Downstream of the collector 4, the EUV illumination light 3 firstly passes through an intermediate focal plane 5, which can be used for separating the EUV illumination light 3 from unwanted radiation or particle portions. After passing through the intermediate focal plane 5, the EUV illumination light 3 firstly strikes a field facet mirror 6. An overall beam of the illumination light 3 has a numerical aper ture a in the intermediate focal plane 5.

In principle, light with a longer wavelength, e.g., DUV light with a wavelength of 193 nm, can also be used as the illumination light 3.

In order to facilitate the description of positional relationships, a Cartesian global xyz- coordinate system is in each case depicted in the drawing. In Figure 1, the x-axis runs perpendicularly to the plane of the drawing and out of the latter. The y-axis runs to ward the right in Figure 1. The z-axis runs upward in Figure 1. In order to facilitate the description of positional relationships for individual optical component parts of the projection exposure apparatus 1, a Cartesian local xyz- or xy- coordinate system is in each case also used in the following figures. The respective lo cal xy-coordinates span, unless described otherwise, a respective principal arrange ment plane of the optical component part, for example a reflection plane. The x-axes of the global xyz-coordinate system and of the local xyz- or xy-coordinate systems run parallel to one another. The respective y-axes of the local xyz- or xy-coordinate sys tems are at an angle with respect to the y-axis of the global xyz-coordinate system which corresponds to a tilting angle of the respective optical component part about the x-axis.

Figure 2 shows, in an exemplary manner, a facet arrangement of field facets 7 of the field facet mirror 6. The field facets 7 are rectangular and have in each case the same x/y aspect ratio. The x/y aspect ratio can be for example 12/5, can be 25/4 or can be 104/8.

The field facets 7 predetermine a reflection surface of the field facet mirror 6 and are grouped into four columns with 6 to 8 field facet groups 8a, 8b each. The field facet groups 8a respectively have seven field facets 7. The two additional field facet groups 8b, on the edge, of the two central field facet columns respectively have four field fac ets 7. The facet arrangement of the field facet mirror 6 has interstices 9, in which the field facet mirror 6 is shadowed by holding spokes of the collector 4, between the two central facet columns and between the third facet line and the fourth facet line.

In a variant not illustrated here, the field facet mirror 6 is constructed as an MEMS mirror array with a multiplicity of tiltable individual mirrors, with each of the field facets 7 being formed by a plurality of such individual mirrors. Such a construction of the field facet mirror 6 is known from US 2011/0001947 Al. After reflection at the field facet mirror 6, the EUV illumination light 3 split into pen cils of rays or partial beams assigned to the individual field facets 7 strikes a pupil facet mirror 10.

The field facets 7 of the field facet mirror 6 are tiltable between a plurality of illumina tion tilt positions, and so this alters the direction of a beam path of the illumination light 3 reflected by the respective field facet 7 and hence is able to alter the point of in cidence of the reflected illumination light 3 on the pupil facet mirror 10. Correspond ing field facets that are displaceable between various illumination tilt positions are known from US 6,658,084 B2 and US 7, 196,841 B2. This facilitates the prescription of an illumination setting, i.e., a distribution of illumination angles for illuminating the object field. Examples of illumination settings are known, inter alia, from DE 10 2008 021 833 Al.

Figure 3 shows an exemplary facet arrangement of round pupil facets 11 on a pupil facet carrier 13 of the pupil facet mirror 10. The pupil facets 11 are disposed around a centre in facet rings lying one inside another. At least one pupil facet 11 is assigned to each partial beam of the EUV illumination light 3 reflected by one of the field facets 7, in such a way that a respective impinged facet pair comprising one of the field facets 7 and one of the pupil facets 11 predefines an object field illumination channel for the associated partial beam of the EUV illumination light 3. The channel-by-channel as signment of the pupil facets 11 to the field facets 7 is implemented on the basis of a desired illumination by the projection exposure apparatus 1.

Below, the pupil facet mirror 10 is also referred to as mirror for measurement. Below, the pupil facets 11 are also referred to as individual facets.

The field facet mirror 6 comprises several hundred of the field facets 7, for example 300 field facets 7. The number of pupil facets 11 of the pupil facet mirror 10 can at least equal the sum of the tilt positions of all field facets 7 of the field facet mirror 6. In a variant not illustrated here, the pupil facet mirror 10 is constructed as an MEMS mirror array with a multiplicity of tiltable individual mirrors, with each of the pupil facets 11 being formed by a plurality of such individual mirrors. Such a construction of the pupil facet mirror 10 is known from US 2011/0001947 Al.

Via the pupil facet mirror 10 (cf , Figure 1) and a downstream transfer optical unit 17 consisting of three EUV mirrors 14, 15, 16, the field facets 7 are imaged into an object plane 18 of the projection exposure apparatus 1. The EUV mirror 16 is embodied as a mirror for grazing incidence (grazing incidence mirror). Disposed in the object plane 18 is an object in the form of a reticle 19, from which, with the EUV illumination light 3, an illumination region in the form of an illumination field is illuminated, said illumi nation field coinciding with an object field 20 of a downstream projection optical unit 21 of the projection exposure apparatus 1. The object field illumination channels are superimposed in the object field 20. The EUV illumination light 3 is reflected from the reticle 19.

An overall beam of the illumination light 3 at the object field 20 has an object-side nu merical aperture NA, which may lie in the range between 0.04 and 0.15, for example.

The projection optical unit 21 images the object field 20 in the object plane 18 into an image field 22 in an image plane 23. Disposed in said image plane 23 is a wafer 24 bearing a light-sensitive layer, which is exposed during the projection exposure by means of the projection exposure apparatus 1. During the projection exposure, both the reticle 19 and the wafer 24 are scanned in a synchronized manner in the y-direction. The projection exposure apparatus 1 is embodied as a scanner. Below, the scanning di rection y is also referred to as object displacement direction. The field facet mirror 6, the pupil facet mirror 10 and the mirrors 14 to 16 of the trans fer optical unit 17 are parts of an illumination optical unit 25 of the projection expo sure apparatus 1. In a variant of the illumination optical unit 25 not illustrated in Fig ure 1, the transfer optical unit 17 may also be dispensed with in part or in full, and so no further EUV mirror, exactly one further EUV mirror or else exactly two further UV mirrors may be disposed between the pupil facet mirror 10 and the object field 20. The pupil facet mirror 10 can be disposed in an entry pupil plane of the projection optical unit 21.

Together with the projection optical unit 21, the illumination optical unit 25 forms an optical system of the projection exposure apparatus 1.

The field facet mirror 6 represents a first facet mirror of the illumination optical unit 25. The field facets 7 represent first facets of the illumination optical unit 25.

The pupil facet mirror 10 represents a second facet mirror of the illumination optical unit 25. The pupil facets 11 represent second facets of the illumination optical unit 25.

Figure 4 shows a further embodiment of a field facet mirror 6. Component parts that correspond to those that were explained above with reference to the field facet mirror 6 according to Figure 2 have the same reference signs and are only explained to the ex tent that these differ from the component parts of the field facet mirror 6 according to Figure 2. The field facet mirror 6 according to Figure 4 comprises a field facet ar rangement with arcuate field facets 7. These field facets 7 are disposed in a total of five columns with, in each case, a plurality of field facet groups 8. The field facet ar rangement is inscribed in a circular boundary of a carrier plate 26 of the field facet mirror 6.

The totality of the field facets 7 are housed on the respective carrier plate 26 of the field facet mirror 6 within an area with dimensions FFx, FFy. The field facets 7 in the embodiment according to Figure 4 all have the same area and the same ratio of width in the x-direction and height in the y-direction, which corre sponds to the x/y-aspect ratio of the field facets 7 of the embodiment according to Fig ure 2.

Figure 5 shows an embodiment of a position- and orientation data measuring device 27 for measuring the position- and orientation data of a mirror and, in particular, of a facet mirror using the example of the pupil facet mirror 10. The position- and orientation data measuring device 27 is used in a method for replacing a mirror in the projection exposure apparatus 1, as is yet to be described below. The mirror for replacement can be the pupil facet mirror 10, the field facet mirror 6 or, in principle, any other mirror, guiding the illumination light 3, of the projection exposure apparatus 1 between the light source 2 and the wafer 24.

The basic structure of such a position- and orientation data measuring device is known from DE 10 2012 209 412 Al.

The position- and orientation data measuring device 27 comprises a light source 28 for measurement light 29. The measurement light can be light with the wavelength of the illumination light 3 or light with a different wavelength, for example in the DUV-, UV- or VIS range. The measurement-light light source 28 can be configured as an LED.

The mirror for measurement is held with a precise position and orientation in a mirror holder 28a, which is only illustrated schematically and in sections in Figure 5.

Proceeding from the measurement-light light source 28, a beam path of the measure ment light 29 is modelled in respect of its beam direction, beam diameter and beam di vergence in such a way that it corresponds to a beam path of the illumination light 3 downstream of the pupil facet mirror 10 within the illumination optical unit 25. Partic ularly in the region of the reflection of the measurement light 29 at the pupil facet mir ror 10 for measurement, the measurement light beam path then corresponds to the illu mination light beam path in the illumination optical unit 25, with the measurement light beam path having the opposite direction to the illumination light beam path.

Measurement light partial beams 29i of the measurement light 29 correspond to the il lumination channels of the illumination optical unit 25.

Following the reflection at the pupil facets 11 of the pupil facet mirror 10 for measure ment, the reflected measurement light partial beams 29i propagate towards a measure ment plane 30, which corresponds to an arrangement plane of the field facet mirror 6. The measurement plane 30 can be understood to be an image plane of an output spot 31 of the measurement-light light source 28. When comparing the measurement light beam path according to Figure 5 with the measurement light beam path according to Figure 1, the measurement plane 30 corresponds to the arrangement plane of the field facet mirror 6, i.e., a field plane of the illumination light beam path, and the position and orientation of the output spot 31 corresponds to the object plane 18.

An arrangement of the individual measurement light partial beams 29i, as measure ment light spots 32 assigned to the individual pupil facets 11, arises in the measure ment plane 30; the arrangement distribution of said measurement light spots corre sponds to the distribution of the field facets 7 on the field facet mirror 6. A deviation of an actual distribution of the measurement light spots 32 from a target distribution, spe cifically the predetermined field facet arrangement within the illumination optical unit 25, is converted by the position- and orientation measuring device 27 into a position- and orientation data difference between actual position- and orientation data of the pu pil facet mirror 10 for measurement and target position- and orientation data, which should be obtained in the case of correct positioning of the mirror for measurement. The position- and orientation data measuring device 27 can be embodied in such a way that it contains no moving component parts.

The component parts of the position- and orientation data measuring device 27, more particularly the measurement-light light source 28, the mirror holder 28a and a meas urement light detection unit 40 disposed in the measurement plane 30 are carried by a common support frame of the position- and orientation data measuring device 27 not illustrated in the drawing.

The measurement light detection unit 40 comprises a spatially resolving detector, for example a CCD or CMOS detector, by means of which it is possible to ascertain an ex act position of the measurement light spots 32 in the measurement plane 30.

When measuring the position- and orientation data of the mirror for measurement, it is not necessary to consider all illumination channels, i.e., all beam paths of the measure ment light partial beams 29i, assigned to all pupil facets 11. It suffices to consider a subset of such illumination channels, said subset corresponding to an illumination set ting in fact used when operating the projection exposure apparatus 1, for example. By way of example, this subset thus can be those pupil facets 11 that are illuminated in the case of an annular illumination setting, a dipole illumination setting or a multi-pole il lumination setting. In an extreme case, it is possible to measure only very few individ ual facets, for example fewer than 10 or fewer than 5 of such individual facets, for ex ample merely one, two or three individual facets.

Figure 6 shows a measurement light beam path of an embodiment of the position- and orientation data measuring device 27 with a variant of such a stop 33 for selecting such an illumination channel subset. Component parts and functions corresponding to those which have already been explained above with reference to Figures 1 and 5, and in particular with reference to Figure 5, are denoted by the same reference signs and are not discussed in detail again. Figure 6 illustrates a measurement light beam path between the output spot 31 of the measurement light source 28 and an intermediate focus 34 upstream of the mirror 10 for measurement, which is disposed in the further measurement light beam path and indicated in Figure 6 using dashed lines. After the output spot 31, the measurement light 29 initially passes through a condenser lens 35, with the aid of which the meas urement light beam path is parallelized. The parallel measurement light beam then passes through the stop 33 and a measurement light portion 29_B, which has not been stopped down, then passes through a focusing lens element 36. The focusing lens ele ment 36 ensures that a stop contour 37 is imaged onto the mirror 10 for measurement such that a subset of the pupil facets 11 lying within this stop contour 37 is impinged by the measurement light 29 there, and consequently the position- and orientation data measuring device 27 equipped thus considers a subset of illumination channels as signed to these impinged pupil facets 11. Using dashed lines, Figure 6 illustrates a hy pothetical marginal beam path 29_A of the entire measurement light beam without stop ping down in the measurement light beam path downstream of the stop 33.

Thus, the lens element 36 represents an imaging optical unit for imaging the stop 33 onto an arrangement plane of the mirror holder of the position- and orientation data measuring device 27.

Figure 7 shows a further embodiment of a stop 38 for selecting a subset of illumination channels assigned to the individual facets, corresponding to the measurement light par tial beams 29i. The function of the stop 38 corresponds to that of the stop 33 according to Figure 6. Component parts and functions corresponding to those which have already been explained above with reference to Figures 1 to 6, and in particular with reference to Figures 5 and 6, are denoted by the same reference signs and are not discussed in detail again.

The stop 38 is disposed as a shadow-casting stop in the measurement light beam path between the output spot 31 and the mirror 10 for measurement.

The stop 38 directly stops down the measurement light beam before the mirror 10 for measurement is impinged.

Below, a further embodiment of a stop 39 for selecting a subset of illumination chan nels assigned to the individual facets is described on the basis of Figure 8. Component parts and functions corresponding to those which were already explained above with reference to Figures 1 to 7, and in particular with reference to Figures 5 to 7, are de noted by the same reference signs and are not discussed in detail again.

In the embodiment according to Figure 8, the stop 39 is disposed in the region of the reflection of the measurement light 29 at the mirror 10 for measurement, the function of said stop corresponding to that of the stops 33 according to Figure 6 and 38 accord ing to Figure 7.

The stop 39 is embodied as a near field stop. The stop 39 is disposed in the vicinity of the mirror holder 28 A.

A method for replacing a mirror in the projection exposure apparatus 1 using one of the above-described embodiments of the position- and orientation data measuring de vice 27 is explained below on the basis of Figures 9 to 17. Component parts and func tions which were already described above on the basis of Figures 1 to 8 have the same reference signs and are not discussed again in detail.

A mirror for replacement, for example the pupil facet mirror 10, is initially removed from the projection exposure apparatus 1 during a removal step 41. In a subsequent in stallation step 42, the removed mirror for replacement is then installed in the mirror holder 28a of the position- and orientation data measuring device 27. Then, the posi- tion- and orientation data of the mirror for replacement are measured using the respec tive embodiment of the position- and orientation data measuring device 27 in a meas urement step 43. Subsequently, the mirror for replacement is removed from the posi tion- and orientation data measuring device 27 again in a further removal step 44.

Now, the replacement mirror, intended to be installed in the projection exposure appa ratus 1 as a replacement for the mirror for replacement, is installed in the mirror holder 28a of the position- and orientation data measuring device 27 in an installation step 45. Now, the position- and orientation data of the replacement mirror are measured by the position- and orientation data measuring device 27 in a subsequent measurement step 46. Then, the replacement mirror is removed from the position- and orientation data measuring device 27 again in a subsequent removal step 47.

Now, position- and orientation data differences between the measured position- and orientation data of the mirror for replacement and the measured position- and orienta tion data of the replacement mirror are calculated in a calculation step 48. Now, the bearing points of the replacement mirror are reworked on the basis of these position- and orientation data differences.

This is still elucidated in greater detail below with reference to Figures lOff

Figure 10 schematically shows a side view of the mirror for replacement on the basis of a pupil facet mirror for replacement with pupil facets 11 and a pupil facet carrier 13 with bearing points 13a, 13b. In a corresponding illustration, Figure 11 shows the re placement mirror in the form of another pupil facet mirror 10T, once again with pupil facets 11 and a pupil facet carrier 13T with bearing points 13Ta, 13Tb. Differences be tween the relative position of, firstly, the bearing points 13a, 13b and, secondly, the bearing points 13Ta, 13 Tb relative to the entire mirror are illustrated with much exag geration in Figures 10 and 11.

Figure 12 shows the mirror holder 28a of the position- and orientation data measuring device 27 with bearing receptacles 49a, 49b, which are assigned, firstly, to the bearing receptacles 13a, 13Ta and, secondly, 13b, 13Tb.

Figure 13 shows the pupil facet mirror 10 for replacement during measurement step 43.

Figure 14 shows the replacement mirror 10T during measurement step 46. On account of the different relative positions of, firstly, the bearing points 13 a, 13b and, secondly, the bearing points 13Ta, 13 Tb, there is a global displacement of the measurement light spots 32, which is indicated schematically in Figures 13 and 14 by a displacement vec tor 50. Calculation step 48 and reworking of the bearing point are implemented, inter alia, on the basis of this global displacement.

Figure 15 schematically shows the result of reworking the bearing points on the re placement mirror 10T. A spacer 51 has been attached in the region of the bearing point 13Ta, and so a resultant bearing point 13Tar now, in terms of its relative position to the remaining pupil facet carrier 13, corresponds to the position of the bearing point 13a of the pupil facet mirror 10 for replacement. Material ablation has occurred during the calculation and reworking step 48 in the region of the other bearing point 13 Tb, and so the resultant bearing point 13Tbr, in terms of its position, corresponds to the position of the bearing point 13b of the pupil facet mirror 10 for replacement.

Figures 16 and 17 show a comparison of, firstly, the pupil facet mirror 10 for replace ment (Figure 16) and, secondly, the replacement mirror 10T (Figure 17) in a mirror re ceptacle 52 of the projection exposure apparatus 1 for holding the respective pupil facet mirror in the illumination optical unit 25.

In the holder of the (original) mirror 10 for replacement, an original spacer 53 is dis posed between the bearing point 13b and an associated receptacle portion of the mirror receptacle 52 for the purposes of optimizing the adjustment. Figure 17 shows the conditions following a final installation step 54 of the replace ment mirror 10T in the mirror receptacle 52 of the projection exposure apparatus 1. On account of the already reworked bearing points 13 Tar and 13Tbr, both the mirror re- ceptacle 52 and the original spacer 53 can be used without modification and the in stalled replacement mirror 10T has exactly the same position and orientation within the illumination optical unit 25 of the projection exposure apparatus 1 as the original mirror 10 for replacement. Measuring 43 the position- and orientation data of the mirror 10 for replacement on the one hand and measuring 46 the position- and orientation data of the replacement mir ror 10T on the other hand is implemented directly in succession and can occur, for ex ample, within a time period of two hours or within an even shorter time period. The measurement steps 43, 46 are implemented at the same location. Thus, there is no displacement overall of the position- and orientation data measuring device 27 be tween the measurement steps 43 and 46.

Then, following the replacement of the pupil facet mirror 10, as explained above, a portion of the reticle 19 is initially projected onto the wafer 24 with the aid of the pro jection exposure apparatus 1. Afterwards, the light-sensitive layer on the wafer 24 that has been exposed with the illumination light 3 is developed.

Claims

Patent claims

1. Method for replacing a mirror (10) in a projection exposure apparatus (1), includ ing the following steps:

measuring (46) position- and orientation data of a replacement mirror (10T), which should be inserted in place of the mirror (10) for replacement, using a position- and orientation data measuring device (27),

reworking (48) bearing points (13Ta, 13Tb) of the replacement mirror (10T) on the basis of ascertained differences between, firstly, position- and orienta tion data of the mirror (10) for replacement and, secondly, the position- and orientation data of the replacement mirror (10T),

installing (54) the reworked replacement mirror (10T) as a substitute for the mirror (10) for replacement.

2. Method according to Claim 1, characterized in that measuring (43, 46) of the po sition- and orientation data of, firstly, the mirror (10) for replacement and, sec ondly, the replacement mirror (10T) is implemented directly in succession.

3. Method according to Claim 1, characterized in that measuring (43, 46) of the po sition- and orientation data of, firstly, the mirror (10) for replacement and, sec ondly, the replacement mirror (10T) is implemented at the same location.

4. Method according to any one of Claims 1 to 3, characterized in that at least one spacer (51) is inserted when reworking (48) the bearing points (13Ta, 13Tb) of the replacement mirror (10T).

5. Method according to any one of Claims 1 to 4, characterized in that at least in stance of material ablation is implemented when reworking (48) the bearing points (13Ta, 13Tb) of the replacement mirror (10T).

6. Method according to any one of Claims 1 to 5, characterized in that said method is applied in the case of a facet mirror (10) as mirror for replacement, wherein the facet mirror (10) comprises a multiplicity of individual facets (11).

7. Method according to any one of Claims 1 to 6, characterized in that an illumina tion beam path within the projection exposure apparatus (1) is reproduced for the purposes of measuring (43, 46) the position- and orientation data.

8. Method according to either of Claims 6 and 7, characterized in that a subset of illumination channels associated with the individual facets (11) is considered when measuring (43, 46) the position- and orientation data.

9. Method according to Claim 8, characterized in that the subset corresponds to an illumination setting of the projection exposure apparatus (1).

10. Method according to Claim 8 or 9, characterized in that the subset is selected by stopping-down the illumination channels that should not be measured.

11. Position- and orientation data measuring device (27) for carrying out a method ac cording to any one of Claims 1 to 10,

comprising a light source (28) for measurement light (29),

comprising a mirror holder (28a) for a mirror (10, 10T) to be measured, comprising a measurement light detection unit (40) in the beam path of the measurement light (29) downstream of the mirror holder (28a),

comprising a stop (33; 38; 39) for stopping-down the measurement light (29) used for the measurement,

comprising an imaging optical unit (36) for imaging the stop (33) onto an ar rangement plane of the mirror holder (28a).

12. Position- and orientation data measuring device (27) for measuring the position- and orientation data of a mirror (10, 10T) comprising a multiplicity of individual facets (11),

comprising a light source (28) for measurement light (29),

- comprising a mirror holder (28a) for the mirror (10, 10T) to be measured, comprising a measurement light detection unit (40) in the beam path of the measurement light (29) downstream of the mirror holder (28a),

wherein the position- and orientation data measuring device is embodied in such a way that a subset of illumination channels associated with the individ- ual facets (11) is considered when measuring the position- and orientation data of the mirror (10, 10T),

comprising an imaging optical unit (36) for imaging the stop (33) onto an ar- rangement plane of the mirror holder (28a).

13. Position- and orientation data measuring device according to Claim 11 or 12, characterized

in that the stop (33; 38; 39) is disposed between the light source (28) and the mirror holder (28a),

in that the stop (39) is disposed close to the mirror holder (28a).